Plz no. All that will do is make one weapon out of all other choices the best and others mute. It would make things unique but lets be honest it will just make everything that doesn't have a good buff suck.

"Hey man wanna do Coil? We missing one person and we're really close to beating T9."
"Naw I'll pass the best lance is from Ifrit EX anyway boosts heavy thrusts dmg boost. Won't ever need another lance."